Mounting a chip onto a ceramic substrate has traditionally involved arranging the chip at a prescribed position on the substrate, and using a wire-bonding device to connect wires from the chip electrodes to circuit paths on the substrate. Nevertheless, hybrid integrated circuit packages have been coming into greater use recently and the trend toward high-function and high-density circuits as well as lighter, thinner, shorter and smaller integrated circuit packages are being adapted to devices for everyday use. These devices are rapidly coming into common use; and, as a result an increasing demand is taking place for low-cost, lighter, thinner, shorter and smaller hybrid integrated circuit packages that make use of direct surface attaching of the chip to the ceramic substrate rather than the use of wire-bounding techniques.
A number of problems exist in conventional technology. In the case of using a wire-bonding device, very thin gold wires are extended between the electrodes of the ceramic substrate and the chip and soldered thereto. This resulted in low efficiency due to the processing operations and the area taken up by the electrodes on the chip and substrate was large. Moreover, the manufacturing was slow.
An effective method of overcoming these problems and satisfying the demands of meeting high production requirements for such low-cost, lighter, thinner, shorter and smaller hybrid integrated circuit packages is to directly solder the electrodes of the chip to the respective electrodes of the ceramic substrate.